The Kinetics Analysis Of Anodic Alumina Templet And Influence Of Pretreatment On Its Morphology

It was rearched on some mechanism models at present for the formation mechanism of the anodic alumina templet. However, investigators didn't attach importance to the dynamics mechanism from the electrolyte and electrode aspect. Therefore, it is necessary to research the dynamics mechanism of anodic alumina templet deeply. This paper has done the following work under the sistuation that can form porous alumina templet with nano-pore array structure:①The curves of current density– time are analyzed during the formation of anodic alumina template at different temperatures, the curves have experienced three stages of declining, rising and going steady. It can be inferred that porous anodic alumina film are able to generate in the appropriate conditions, and the speed of electrochemical reaction also increases with the increase of temperature.②Reactions which take place on cathode and anode are analyzed, and the concentration of aluminum ion is mensurated by aluminum reagent spectrophotometry insulfuric acid electrolyte of 1.0 mol / L. Then, basing the chemistry dynamics theories, the reaction that aluminum loses electronics is confirmed zero order reaction, and the velocity constants are ascertained at different temperature by makeing temperature for variable, so the apparent activation energy can be confirmed basing Arrhenius equation, and the apparent activation energy is 53.80 kJ·mol-1. Theoretically, the low temperature is advantageous to the reaction which has low apparent activation energy, and the the experiment's requests are even the same as the theory's.③Basing the analysis of Tafel curves, the electrode dynamics parameters and the reaction course are ascertained,When scholars research the preparation of anodic alumina templet, applications, and the formation mechanism, it is required to go through some miscellaneous pretreatment procedures. To simplify the pretreatment process for prepaing anodic alumina templet, the influence of annealing, degreasing, chemical polishing on the morphology of anodic alumina templet are investigated in this thesis. During the experimental process, anodic alumina templets are prepared under constant potential by DC in oxalic acid solutions of 0.13mol/L through a two-step anodic oxidation. The morphology of anodic alumina templet is observed by atomic force microscope, and the influences of each step of pretreatment process on the characteristics of anodic alumina templet are discussed by analyzing the current change in the initial process of anodic oxidation. The following conclusions are gotten in this parer:①It can be indicated that anodic alumina templets are successfully prepared by observig with atomic force microscope, the anodic alumina templet is compose of a many six-cylinder-shaped cells, the average diameter of pores is basically the same size with each other about 200 nm, the hole density is 109 / cm2, and the holes distribute evenly in an orderly manner.②The influence of each pretreatment procedure on the morphology of anodic alumina templet is investigated, and regular anodic alumina templet is successfully prepared under the conditions of the simplification. A series of comparative experiments show that after degreasing, well-arranged porous alumina films are obtained without annealing, chemical polishing and removing natural oxide layer, and it makes the preparation of porous alumina films simplified.